3c7b30f704
The BCM2835 pinctrl driver acquires a spinlock in its ->irq_enable, ->irq_disable and ->irq_set_type callbacks. Spinlocks become sleeping locks with CONFIG_PREEMPT_RT_FULL=y, therefore invocation of one of the callbacks in atomic context may cause a hard lockup if at least two GPIO pins in the same bank are used as interrupts. The issue doesn't occur with just a single interrupt pin per bank because the lock is never contended. I'm experiencing such lockups with GPIO 8 and 28 used as level-triggered interrupts, i.e. with ->irq_disable being invoked on reception of every IRQ. The critical section protected by the spinlock is very small (one bitop and one RMW of an MMIO register), hence converting to a raw spinlock seems a better trade-off than converting the driver to threaded IRQ handling (which would increase latency to handle an interrupt). Cc: Mathias Duckeck <m.duckeck@kunbus.de> Signed-off-by: Lukas Wunner <lukas@wunner.de> Acked-by: Julia Cartwright <julia@ni.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| pinctrl-bcm281xx.c | ||
| pinctrl-bcm2835.c | ||
| pinctrl-cygnus-mux.c | ||
| pinctrl-iproc-gpio.c | ||
| pinctrl-ns2-mux.c | ||
| pinctrl-ns.c | ||
| pinctrl-nsp-gpio.c | ||
| pinctrl-nsp-mux.c | ||